Various medical procedures require the accurate localization of a three-dimensional position of a surgical instrument within the body in order to effect optimized treatment. For example, some surgical procedures to fuse vertebrae require that a surgeon drill multiple holes into the bone structure at specific locations. To achieve high levels of mechanical integrity in the fusing system, and to balance the forces created in the bone structure, it is necessary that the holes are drilled at the correct location. Vertebrae, like most bone structures, have complex shapes including non-planar curved surfaces making accurate and perpendicular drilling difficult. Conventionally, a surgeon manually holds and positions a drill guide tube by using a guidance system to overlay the drill tube's position onto a three dimensional image of the bone structure. This manual process is both tedious and time consuming. The success of the surgery is largely dependent upon the dexterity of the surgeon who performs it.
In surgery involving driving a sharp object such as a needle, drill or screw into bone, a challenge is to prevent the tip of the sharp instrument from wandering away from the intended location of penetration. Driving or drilling a sharp instrument into bone may be relatively easy when the tip of the instrument is perpendicular to bone, wandering or sliding (“skiving”) of the tip may become problematic as the bone surface being penetrated becomes steeper. This is due to the tool-bone reaction force component that is parallel to the bone surface becoming greater at steeper angles.
Thus, there is a need to prevent skiving or unintended movement of a surgical instrument during medical procedures. This may be accomplished as noted in the present disclosure using robot-assisted surgical techniques.